Process of decaffeinating coffee-beans.



L. KLEIN. PROCESS OF DEGAFFEINATING COFFEE BEANS.

APPLICATION FILED OCT. 5, 1910.

Patented Oct. 1, 1912.

2 SHEETS-SHEET 1.

APPLICATION FILED OUT. 5, 1910.

Patented Oct. 1, 1912.

2 SHEETS-SHEET 2,

LOUIS KLEIN, 0F STRASSBURG, GERMANY PROCESS OF DECAFFEINATINGCOFFEE-BEANS inseam.

Specification of Letters-Patent.

Patented Get. 11, rate.

Application filed October 5, 1910; Serial No. 585,514.

'1 '0 all whom it may concern:

Be it known that-l, LOUIS KLEiN, a sub ject of the German Emperor, andresiding at Strassburg, rlrlsacc-Lorraine, German Empire, have inventedcertain new and use ful Improvements in Processes of Decaffeinat-ingCotleelleans, ofwhic'h the following is a specification.

Tie present invention relates to improvements in proc for treatingcotiee-beans with a view of e..tracting therefrom the catfeimwvithout inany way injuriously affecting the *aluable constituents of the beans.

in the known processes of depriving cofiee beans of their catl'ein, thelatter is extracted from the previously steam-heated, loosenedup beans,and after the catlfein salts are decomposed into vapor or gas by meansof suitable acids or alkalis, by treating them with yolatilesolvents,such as alcohol, benzol and the like, or mixtures thereof.These procedures, however, are more or less troublesome andtime-consuming, requiring also complicated and necessarily expensive apparatus, and are suitable only for working up raw beans, and furthermorethe extraction of the catleiu can practically not be carried belowOxlfli, and at that entails a considerable loss (about 2 25%) of thoseconstituents upon which the taste and the aroma depend.

The object of this invention is to provide a process to which the abovespecified and other disadvantages do not attach, and the processessentially consists in obtaining the within extraction without previousdecom' position of the catl ein-salts, by employing mixtures of two ormore alkali catt'ein solvents, in simple, ordinary apparatus. Thetechnical progress involved in the use of such alkali mixtures oversingle alkali solutions essentially consists in the possibility ofcarrying the extraction of the catl'ein to any desired degree,practically to a percentof 0.1.5 and still lower, without at the verymost losing more than 1.52% of the extraction substances, depending uponthe nature of the mixture of alkali solvents used. r

I am well aware that it is old to treat raw or roasted beans, in wholeor broken state, .fOI' the purpose of catlein extraction with suctionmeans.

have the disadvantage that the beans are cannot be carried beyondleaving a eattein percentage of about 0.4:5%.

A further advantage of my improved process is that it can be carried outwithout material modification with raw as well as.

with roasted beans in unbroken state.

As an example of the new process ll will now describe it in thetreatment of raw or green beans. f

Vt ithout any pretreatment 1.00 kilograms of raw beans are dumped into apressure boiler, provided with a stirrcr, and four to five times as muchof a hot alkali mixture, for instance a solution of lime and soda inwater, is poured on the charge. This mix ture is prepared just previousto use by slaking 10 kilograms of quick lime in 50 liters of water, whenslaked lime water results in which slaked lime is still suspended. Tothis solution is then admixed l kilogram of sodaash. Underconstantstirring the mass is then gradually heated to a temperature ofabout 200 C. by introduction of steam and is kept at this temperatureuntil the beans begin to swell. The evaporating water at first isconducted away by suitable The beans are now placed into a roaster ofordinary construction and are first'dried and then heated to atemperature of 160 C. If necessary the beans are then treated againwithin the roaster with a fresh charge oi": lime and soda or othersuitable mixture, and the described cycle of operations is repeateduntil the desired de gree of extraction obtains. After the terminationof the extraction process proper, which, depending on the properties ofthe beans treated, may vary from 3-5 hours, the beans are simply washedonce or several times for removing the adhering extraction substances;they are next dried and roasted and are then ready for consumption.

Some terms of apparatus suitable for car- .r in into )ractic'e 1n)rocess and'modifications thercoi are represented by way of example inthe accompanying drawing, where- 1n:

Figure 1 'is an elevation showing apparatus suitable for carrying intopractice my process as above described; Fig. 2 is a likeview of amodified form of apparatus for a modification of my process, while Figs.3 and 4 are side elevation, partly insection, and transverse section,respectively, showing another form of apparatus for another modificationof my process.

Referring firstly to Fig. 1, an important advantage of the apparatushere shown is that it is of very simple construction and can be employedwith any existing roasting device. Onthe furnace a, made in knownmanner, is placed a mixing vessel Z) which can be heated by the latter,and water requisite for dissolving the chemicals supplied through thehopper c is supplied to this vessel by the pipe d having a stopcock e.For preventing these materials settling and for obtaining a uniformmixture I provide in the mixing vessel 5 a stirrer, not shown, ro-

tated by the belt-driven pulley f. The supply. p'ipe d alsohas at asuitable place a discharge-cocky for preventing water freezing in thepipe in winter, and a gage-glass h is arranged on the mixing vesselitself for determining the level of the liquid. A dischargepipe Is,capable of being closed by the cock 2', leads from the bottomof themixing vessel to about the center of the jacketed roasting drum Zarranged in the illustrative embodiment laterally of the furnace andterminates in a swing discharge-cock m having a nozzle which can beinserted, when desired, into the aperture or peephole provided in thefront wall of the drum. As mentioned above, the coffee-beans remain forabout an hour at a temperature of about 200 C. in the boiling solutionof chemicals in the roasting drum, whereupon the'liquid is run offthrough two openings which are provided in the closed drum and arenormally closed by plates which open outwardly automatically, ashereinafter described. After the operation in question has been repeatedsomefew times, cold or hot water is allowed to How from a tank 39 intothe drum until the coffee is sufficiently washed. In the illustrativeembodiment I arrange, to this end, at the hopper 7?, a water tank 39which is provided with a gage-glass 0 and is connected by the pipe 9 tothe water supply pipe of. The discharge pipe 7- of the tank likewiseopens through an opening in the front wall into the roasting drum 1 andthe flow of water is regulatedby the stopcock s. This apparatus ismanipulated very simply as follows: The heated alkalimixture is suppliedto the green or preliminarily-roasted beans in the roasting drum fromthe mixing vessel by turning the revoluble nozzle of the cock m into itshole in the wall of the drum and opening the wheel t.

prevented from falling out by perforated plates or the like placed overthe openings.

These out-lets can be opened and closed, for example, by plates operatedby the hand- The entire solution which runs out of the drum after thecoffee-beans have been treated is received in a receptacle in order, 1fdesired, to obtain therefrom the cafi ein for further employment.

'As the above described method of extraction is somewhat troublesome andoccupies much" time, however, particularly when the ,removal of thecafiein is to be carried as far as posslble, I preferably employ theheroinafter-described modification of my process.

The raw, non-disintegrated beans are first softened for 3 to 5 hoursaccording to the.

kind and origin of the coffee in a cold mix-- v.ture of alkalis, c. g.slaked lime and soda.

After this preliminary treatment the beans are placed into a specialroasting drum, or one specially constructed for this purpose, graduallyheated to about 180 (3., ex JOSGd to a current of steam at 2 to 5 atmospieres pressure above atmospherlc and then to a .hot mixture of alkalis.After again supplying a current of steam, the beans now contaming butlittle caifein are washed and cleaned in the usual manner in freshwater, the attaching particles of the precipitated chemicals andextracted substances being washed away, which operation may be repeated,if desirable. The beans are then roasted partially or completely in awell- .known manner.

The action'of the steam and solvents lasting altogether for v5 to 15minutes opens the beans still more so that the removal of the cafieincan be carried considerably farther, as compared with all processesknown heretofore for the same purpose, in spite of the considerableshortening of the time of extraction, without occasioning an increasedloss of extractin sub stances. Further, owing to this rapid extractionthe additional advantage is obtained that, in contradistinction to slowmethods of extraction, only an exceedingly small quantity of thearomatic constituents of the beans is extracted, so that non-cafi'ciniccofiee obtained in this manner retains the flavor andv aroma of ordinarycoffee. This modification of the pr ocess forming the subject-matter ofmy invention obviously necessitates a modification of the apparatusrequisite for carrying the same into practice consisting substantiallyin the mixing vessel,

a i in weasel used for prodncin the hot solution of the extractingagcnt,. being simultaneously formed as a vaporizer, so that thealternate treatment oi the coffee-beans with steam and solvents, e. g.during the i reliminary roasting process, cantake place very rapidly.

Fig. 2 shows apparatus for carrying into practice the above describedmodified process of obtaining cotiee beans free from catit'ein. Theapparatus comprises a mixing vessel n on the furnace a which in largeroasters is generally arranged. laterally of: the roaster; fresh wateris supplied to the vessel n through the pipe n having the stopcock w,and the chemicals for the extraction of the caffein through the pipe yhaving the stopcock 2. Inside the mixing vessel '0 is a stirrer, notshown, rotated by bevel-wheel gearing 1 driven by a pair of belt pulleys3 able to be influenced by a belt-shifter 2, Two gage-glasses 1 areprovided on the mixing v .ssel for supervising the level of the liquidtherein, and a bib-cock 5 having a swing nozzle 6 is provided the bottomofthe vessel n for running oil? the liquid it necessary. In order toemploy the'inixing vessel simultaneously as a steam generator it is onlyfilled with water to the top mark of the higher rage-glass. The pressureof the steam forming when the vessel is heated is read on a manometer 7of known kind provided on the vessel. while a safety valve 8 of knownkind provided for preventing explosion. 'A pipe 9 dividing below astopcock 10 into two branch pipes 11, is con nected with the top of themixing and evapcrating vessel 0 for conducting away the steam which isproduced at a pressure of 2 to 5 atmospheres above atmospheric. Thesebranches open into two pipes 12, each having a stopcock 13, connected tothe two ends of the drum 14c and to the bottom the mixing vessel andserve for supplying steam and solvent to the roasting drum 1% where theyact on the beans which have been previously treated it necessary. Forthe purpose of leading the steam away into the'open air when the actionof steam is not necessary,'a branch pipe 15, having a stopcock 1.6,

is connected to the main pipe 9. Furthen for supplyii'ig' fresh water tothe drum 14, a

pipe 18, having a stopcock 17, and fedfrom a fresh water tank 20 mountedon the hopper 19 of the roasting apparatus, opens into the front and, iidesired, into the rear wall of the drum. This modified form of myapparatus is used as follows:Ai ter the solvent, 6. 9. water, and thechemicals, 6. g.'

caustic lime and soda, have been supplied to the mixing vessel 0)through the pipes w and 3 the stirrer is started by operating thebeltshifter 2 and the entire contents of the vessel. n is heated toabout 150 to 180 C.' As soon as the requisite pressure of steam isobtained and the coffee-beans, treated preliminarily, it necessary, havebeen fed in the meantime into the roasting drum through the hopper19 andheated to about 180 C., by opening the stopcock 10 steam is suppliedthrough the two branches 11 to the feed pipes 12, enters into the drum14 and acts on the beans. stopcocks 13 of the pipes 12 are opened andthe necessary quantity of the solvent of caliein is supplied from themixing vessel '0 into the roating drum. After closing the saidstopcocli's 13 steam is again supplied through the steam pipe 9,whereupon this pipe is again closed by turning the stopcock 10. Byopening the stopcock 17 fresh water isthen supplied through the pipe 18from the tank 20 to the beans thus treated, whereby the beans arepurified and particles of chemical and other origin adhering to them arewashed away. .A'fter the washing operation has terminated in the desiredm an ner the beans are roasted completely in the usual manner.

The above described modes of obtaining cofleebeans free from eaiiein bymeans of an alkaline mixture are limited inasmuch as, on the one handwhen the beans are treated at a moderate temperatinre the catit'ein canbe extracted only to a certain degree and, on the other hand, whenhigher temperatures are used with the action of steamalthough theextraction of the catlein is .more perfect, the substances which are'consists in treating the beans by means of' an alkaline mixture at avery moderate tom perature and employing the pressure of a gas producedby suit-able chemicals. 'To this end, the beans are softened in theusual manner in a. solution of alkalis or the like, but are subsequentlyexposed to the action of gases, as e. 9. carbon dioxid, which arenon-injurious to the beans and by the addition of suitable chemicals, ase. g. sodium carbonate and potassium tartrate, produce in the extractionliquid the pressure requisite for the further extraction of thecafi'ein. In this manner the extraction can be continued until a residueof about 0.181% remains when the maximum loss of extracting substances(1.5%) remains the same. For economically carrying into .practice thismodification of -my process any desired roasting drum may be employed,but I prefer to carry this process into practice in a device independentof the' roasting drum, such as is represented in Figs. 3 and 4.Referring to these figures, a drum 24 forming the extraction vesselproper is revoluble in the ends of a drum-like vessel 21 provided with apreferably detachable hopper 22 and After some minutes the an outlet 23..This drum 24 is" driven in known manner by belt-driven spur gearing 26,27 mounted on the frame 25' and can also be rotated by hand by ahand-wheel 28 provided at the opposite end. Obviously this hand-wheel isnecessary when the inlet of the drum 24, which is closed by a cover 29,having a cock, by means of screws or pivotal screw-bolts, is not underthe hopper 22. Further, inside the drum 24 are one or more pockets 80,31 for holding the chemicals necessary for generating a gas and soplaced that their contents do not come into contact with the extractionliquid at the beginning of the process. This process is used as follows:After the beans have been placed into the drum 24 and have softenedsu'tliciently long in the extraction liquid therein a suitable quantityof the chemicals, such as e. g. sodium bicarbonate and potassiumtartrate, for generating the gas is put into the two pockets 30, 31.VVhenthe drum 2 1- is started rotating these substances fall out ofthe'pockets into the extraction liquid.

The dissolving chemicals act on one another and generate a gas, in thesupposed case carbon dioxid, which, as experiments have shown, increasesthe extraction of the catfein, owing to the pressure produced, to suchan extent that after the beans have been treated altogether for 3 to 5hours the percentage of eattein in the same amounts,

as mentioned above, to only 0.181%.

I claim l l. The hereindescribed process of decaflfeinating coffeebeans, which consists in subjecting the beans to the action of liquidalkali mixtures capable of dissolving caffein, substantially as settort-bl 2. The hereindescribed process of decafteinating cofi'ee beans,which consists-in subjecting the beans to the action of a mixture of aplurality of alkali solutions capable of dissolving catfein,substantially asset forth.

3. The hereindescribed process of decaffeinating coffee beans, whichconsists in subjecting the beans to the action of alkali mixtures and ofpressure gases capable of dissolving catfein, substantially as setforth.

4. The hereindescribed process of decaffeinating coliee beans, which.consists in subjecting the beans to the action of alkali mixturescapable of dissolving cal'l'ein and of pressure gases generated bycausing suitable agents to react with said alkali mixtures,substantially as set forth.

5. The hereindescribed process of decaffeinating cofiee beans, whichconsists in subjecting the beans to the action of liquid alkali mixturescapable of dissolving caftein until the beans swell up, drying them,repeating the operations as required washing the product, and thenroasting it, substantially as set forth.

(3. The hereindescribed process of decaffeinating coffee beans, whichconsists in soaking the beans in cold liquid alkali mixtures capable ofdissolving cafltein, steaming the beans, subjecting them to the actionof hot alkali i'nixtures, then washing. and finally roasting them,substantially as set forth.

In testimony whereof I ailix my signature in presence of two witnesses.

LOU IS KLl )IN. lVitnesses Jon Barn, AUeUsr OOSTERMAN.

